Mind machines, also known as psychowalkman, use pulsing rhythmic sound and/or flashing light to alter brainwave frequencies, using brainwave synchronisation/brainwave entrainment. Mind machines (psychowalkman) induce deep states of relaxation, concentration, altered states of consciousness. often compared to those obtained from meditation and shamanic exploration.

Mind machines are often geared towards directing the average brainwave frequency from a high level to a lower level. Target frequencies typically correspond to delta (1-3 hertz), theta (4–7 Hz), alpha (8–12 Hz) or beta brain waves (13–40 Hz), and can be adjusted by the user based on the desired effects.